How Do Starfish Eat?
A starfish’s mouth, underneath its flat body, leads directly into a large, bag like stomach. The starfish can push its stomach out through its mouth. Starfish like to eat clams and oysters. Encircling a clam with its powerful arms, the starfish attaches its sucker like tube feet to the clam’s shell.
With ever-increasing force, it pulls the two halves of the shell apart. Then the starfish pushes out its stomach and digests the food. When the starfish has completed its meal, it pulls back its stomach, and leaves only an empty clam shell behind. Starfish mouths aren’t very big, so the two-stomach system allows a starfish to eat prey that wouldn’t fit inside its mouth!
Starfish that don’t have suction disks swallow prey whole and afterwards eject undigested parts. The unusual method of digesting prey outside their bodies allows starfish to eat animals considerably larger than their tiny mouths. Besides oysters and clams, they feed on mussels, arthropods and fish. Some species supplement their diets with algae and other organic matter.